Electrical devices such as electrical connectors typically have an electrical cord or cable extending outwardly from the device. It is necessary to securely fasten the electrical cord or cable to the electrical device or connector to prevent the electrical conductors from being pulled from their terminations, which can damage the conductors and the electrical device. If the electrical conductors are pulled or torn away from their terminations in the electrical device or connector, this can result in the electrical device or connector becoming inoperable, and in certain circumstances can result in serious injury to the user due to shorting of the electrical current being carried in the conductors.
Accordingly, many corded electrical devices or connectors have a strain relief assembly for gripping and coupling the electrical cord or cable thereto, and for maintaining slack between the ends of the conductors and their respective terminals or electrical connections within the electrical device or connector. Presently, there are a wide variety of strain relief assemblies available for electrical devices or connectors. For example, many electrical devices or connectors have a pair of cord or cable clamping members for gripping and coupling the electrical cord thereto. Typically, one of the cord or cable clamping members is stationary, while the other cord or cable clamping member is movable in a direction substantially perpendicular to the longitudinal axis of the electrical cord. The clamping members may include a rib or a series of ribs for engaging the electrical cord to ensure a good grip on the electrical cord.
Examples of some prior electrical connectors having a strain relief assembly with a stationary clamp and a movable clamp are disclosed in the following U.S. Pat. Nos.: 3,393,395 to Hubbell; 3,784,961 to Gartland, Jr.; 3,904,265 to Hollydale et al; 4,080,036 to Hagel; 4,178,056 to Lee; 4,213,667 to Wittes; 4,931,023 to Browne; 5,217,389 to MacKay et al; 5,304,075 to Hoffman; and 5,338,222 to Boteler.
However, these types of strain relief assemblies are often not suitable in certain circumstances and have certain drawbacks. For example, during clamping of the electrical cord, the installer must push the electrical cord towards the terminals and hold the electrical cord in this position, while at the same time tighten down the movable clamping member on the electrical cord. Moreover, some of these types of external clamps typically require a set of screws in addition to the screws for the electrical connector housing. Thus, this increases the costs of manufacturing such electrical connectors.
Examples of some other prior electrical connectors with internal strain relief are disclosed in the following U.S. Pat. Nos.: 3,437,980 to Smith; 3,856,376 to Poliak et al; 4,108,527 to Douty et al; 4,138,185 to Jaconette, Jr.; 4,208,085 to Lawrence et al; 4,561,715 to Sanchez; 4,721,483 to Dickie; 4,722,580 to Kocher et al; 4,749,369 to Wang; 4,921,441 to Sauder; 4,963,104 to Dickie; and 5,277,619 to Yamamoto.
However, these types of strain relief assemblies also suffer certain disadvantages. For example, some of the strain relief assemblies increase difficulty of assembling the electrical connectors. Moreover, some of these strain relief assemblies are difficult to manufacture and require special molding procedures which can significantly increase the total cost of the electrical connectors.
In view of the above, it is apparent that there exists a need for an electrical cord clamp for an electrical device or connector which will overcome the above-mentioned problems of the prior art devices. This invention addresses this need in the art along with other needs which will become apparent to those skilled in the art once given this disclosure.